md: Fix read balancing in RAID1 and RAID10 on drives > 2TB
read_balance uses a "unsigned long" for a sector number which
will get truncated beyond 2TB.
This will cause read-balancing to be non-optimal, and can cause
data to be read from the 'wrong' branch during a resync. This has a
very small chance of returning wrong data.
Reported-by: Jordan Russell <jr-list-2010@quo.to>
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index e0742c4..a1f5fd2 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -495,7 +495,7 @@
*/
static int read_balance(conf_t *conf, r10bio_t *r10_bio)
{
- const unsigned long this_sector = r10_bio->sector;
+ const sector_t this_sector = r10_bio->sector;
int disk, slot, nslot;
const int sectors = r10_bio->sectors;
sector_t new_distance, current_distance;